Analog Devices Inc. ADM825MYRJ-R7

Overview

ADM825MYRJ-R7 from Analog Devices is a supervisory circuit with manual reset input and dual push-pull reset outputs, designed for microprocessor supply voltage monitoring and system-level fault recovery. It features a 4.38 V reset threshold (±0.05 V), 140 ms minimum reset timeout, guaranteed reset validity down to VCC = 1 V, and operates across −40°C to +125°C for automotive and industrial control applications.

For engineers reviewing the ADM825MYRJ-R7 datasheet, ADM825MYRJ-R7 pinout, ADM825MYRJ-R7 application, or ADM825MYRJ-R7 equivalent, key selection criteria include reset threshold accuracy, manual reset pulse width tolerance (≥1 µs), MR internal pull-up (52 kΩ), dual active-low/active-high output drive capability, and SOT-23-5 package compatibility with space-constrained embedded systems.

Technical Context

The ADM825MYRJ-R7 implements a precision bandgap-based voltage reference and comparator to monitor VCC against a factory-trimmed 4.38 V threshold with ±0.05 V tolerance over temperature. Its reset generator enforces a fixed 140 ms minimum assertion period after VCC rise, MR deassertion, or brownout recovery - independent of supply slew rate or noise.

Unlike the ADM823/ADM824 variants, the ADM825MYRJ-R7 omits watchdog functionality but integrates a dedicated manual reset input (MR) with on-chip debounce and 100 ns glitch rejection. Its dual push-pull RESET/RESET outputs deliver rail-to-rail logic levels with 0.3 V low-state voltage at 1.2 mA sink and 0.8×VCC high-state voltage at 30 µA source - ensuring reliable interface with diverse microcontroller reset inputs.

Key Specifications

Pinout & Package

ADM825MYRJ-R7 is housed in a 5-lead SOT-23 package (JEDEC MO-178-AA, RJ-5), measuring 2.90 mm × 1.60 mm × 1.15 mm, with gull-wing leads and 0.95 mm lead pitch. The package supports reflow soldering per J-STD-020 and offers θJA = 270°C/W thermal resistance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar supervisory circuit applications.

Compared with ADM825MYRJ-R7, ADM823MYRJ-R7 adds watchdog capability at the expense of dual reset outputs, while TPS3808G33DBVR trades manual reset and push-pull drive for lower unit cost and tighter 3.3 V threshold - making each suitable for distinct system-level reset architecture priorities.

Availability

ADM825MYRJ-R7 is available at Aetrix Electronics and suitable for automotive engine control units, industrial programmable logic controllers, and smart energy metering systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ADM825MYRJ-R7 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA, with design centers and manufacturing facilities worldwide.

The ADM825 belongs to Analog Devices' precision supervisory circuit product line, engineered specifically for robust power-on reset, brownout protection, and manual system recovery in automotive, industrial, and medical electronics where reliability under voltage stress is critical.

FAQ

What is the reset threshold voltage of the ADM825MYRJ-R7?

The ADM825MYRJ-R7 has a nominal reset threshold of 4.38 V, with a guaranteed range of 4.25 V to 4.50 V across the full −40°C to +125°C operating temperature range. This value is factory-trimmed and specified in the Ordering Guide and Table 2 of the Rev. D datasheet, confirming its suitability for 4.5 V nominal supply monitoring with adequate margin.

Does the ADM825MYRJ-R7 include a watchdog timer function?

No, the ADM825MYRJ-R7 does not include a watchdog timer. Per Table 1 and the General Description in the Rev. D datasheet, the ADM825 variant is defined by manual reset input (MR) and dual push-pull RESET/RESET outputs - unlike the ADM823 and ADM824 which integrate watchdog functionality. The ADM825MYRJ-R7 is optimized for applications requiring reliable manual and power-fail reset without code-execution monitoring.

What package type and dimensions does the ADM825MYRJ-R7 use?

The ADM825MYRJ-R7 uses a 5-lead SOT-23 package (JEDEC MO-178-AA, package option RJ-5), with body dimensions of 2.90 mm × 1.60 mm × 1.15 mm and 0.95 mm lead pitch. Figure 21 and the Ordering Guide confirm this mechanical form factor, which supports standard pick-and-place assembly and reflow soldering per J-STD-020.

How does the manual reset (MR) input behave on the ADM825MYRJ-R7?

The MR input on the ADM825MYRJ-R7 is active-low, internally pulled up to VCC via a 52 kΩ resistor, and requires a minimum pulse width of 1 µs to assert reset. As described in Table 4 and the Circuit Description section, it includes on-chip debounce and rejects glitches shorter than 100 ns - enabling direct connection to mechanical switches or GPIOs without external RC filtering.

Can the ADM825MYRJ-R7 operate reliably at VCC = 1 V?

Yes, the ADM825MYRJ-R7 guarantees valid RESET and RESET output states down to VCC = 1 V, as explicitly stated in the Features list and confirmed in the RESET Output section of the Rev. D datasheet. This ensures deterministic reset behavior during severe brownout events, though full functionality (e.g., MR input recognition) is specified down to VCC = 2.38 V per the ADM82xZ/Y operating range.